A mine detection rat is given banana as a reward after successfully identifying an inactive mine on July 2, 2015 in Siem Reap, Cambodia. The Cambodian Mine Action Center (CMAC) working with the Belgian NGO APOPO has recently begun testing the feasability of using large mine detection rats from Tanzania to help clear fields of mines and unexploded ordnance in one of the most bombed and mined countries in the world. (Photo by Taylor Weidman/Getty Images)

A picture made available on 17 September 2014 shows extreme athletes resting in hammocks on webbings stretched between rocks during the International Highline Meeting in Monte Piana, near Misurina, in the northern Italian Alps, Italy, 08 September 2014. (Photo by Balazs Mohai/EPA)

A Sikh warrior, wearing a huge turban attends the annual fair of “Hola Mohalla” in Anandpur Sahib, in the northern Indian state of Punjab, Monday, March 17, 2014. Believers from various parts of northern India collect at the religious fair to celebrate the festival of Holi in a tradition set by the tenth Sikh guru Guru Gobind Singh in the seventeenth century. Nihangs, or Sikh warriors, display their martial skills and attire during the fair, believed to be maintained in the exact tradition as set by the Guru. (Photo by Altaf Qadri/AP Photo)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)

A traffic police woman whistles at a pedestrian, Monday, July 27, 2015, in Pyongyang, North Korea where its citizens are having a one-day national holiday to celebrate the country's 62nd anniversary of the armistice that ended the Korean War. (Photo by Wong Maye-E/AP Photo)

Maudy – Kalulushi, Zambia. Maudy was born in a hut in a small village close to Kalulushi, in Zambia. She grew up playing in the street with the other children in the village, who all attend the same school, where students ages 3 to 10 years old are in the same class. The village has no shops, restaurants or hotels, and just a few children are lucky enough to have toys. Maudy and her friends found a box full of sunglasses on the street, which quickly became their favorite toys. “Toy Stories” project. (Photo and caption by Gabriele Galimberti)

Women wearing bikinis and Santa Claus hats participate in a promotional event to celebrate the upcoming Christmas at a ski resort in Xuchang, Henan province, December 23, 2014. Ten women wore Santa Claus-themed bikinis to welcome the coming Christmas in temperatures below zero Celsius. (Photo by Reuters/Stringer)

A woman plays around as she walks across a glass-bottomed suspension bridge in a scenic zone in Pingjiang county in southern China's Hunan province Thursday, September 24, 2015. The bridge, 300 meters (984 feet) long and 180 meters (590 feet), opened to visitors on Thursday for the first time since its conversion from a regular suspension bridge was completed. (Photo by Chinatopix Via AP Photo)